I am starting to buy parts for my first AR. I would like to shoot a variety of different bullet weights. I am leaning toward a carbine 1 in 9. Is there any appreciable difference in accuracy out to 250-300 yds vs. a 20" barrel in the same twist rate? I am looking for a rifle that is kind of a jack of all trades. I thought the 16" would be easier to handle for defensive purpose but I would still like to be able to blister the coyotes at a couple hundred yards. I will shoot mostly 55grn fmj for plinking but would also like to load a little heavier for coyotes. I'm not looking for a match grade rifle without paying for it, but I also would like to get the most bang for my buck. Pardon the pun. Any thought or suggestions?